The invention relates generally to mechanisms for flushing toilet bowls and, more particularly, to such mechanisms for selectively causing either a lesser quantity of flushing water to be delivered to the bowl from the reservoir tank or, when desired, a maximum quantity of water to be delivered. Such two-stage systems conventionally utilize either a vertically movable ball valve or a pivoted flap valve, in either case with associated mechanism, to control the passage of water from the reservoir tank to the toilet bowl, and the present invention is primarily concerned with mechanism for providing a two-stage operation by a mechanism including a pivoted flap valve.
In the United States patent to Street, No. 3,964,109, there is disclosed a mechanism providing two-stage operation utilizing two pivoted flap valves, while in the U.S. Pat. to Coffman, No. 3,823,425, there is disclosed in FIGS. 12 to 15 a two-stage system utilizing a single flap valve but comprising a very complicated apparatus for controlling the two-stage operation of the valve. These patents are illustrative of the pertinent prior art with respect to the present invention, and it will be seen that the two-stage flap valve operating systems of the pertinent prior art are complicated, with consequent added initial cost and maintenance costs and problems.
It has therefore been the object of this invention to provide a simple and effective operating mechanism for selectively providing either a lesser or a greater flushing operation for a toilet bowl, utilizing only a single flap valve, with consequent saving in initial and maintenance costs and improved operation.